Copper

Copper is a special kind of metal known as a chemical element, with the symbol Cu and atomic number 29. It is soft, easy to shape, and can be stretched into thin wires. Copper is very good at conducting heat and electricity, which makes it very useful.

People have used copper for thousands of years. It is one of the few metals found in nature in a form that can be used directly. Early humans used copper for tools, and later they learned how to mix it with other metals to make even stronger materials like bronze.

Copper can be found in many everyday things. It is used in buildings, especially for roofs, and it is part of many metal mixtures like those used in jewelry and coins. Copper also has important roles in living things, helping with processes that need oxygen.

Etymology

The word "copper" comes from old words that people used a long time ago. In Latin, people called it aes cyprium, which means "metal of Cyprus." Later, in Late Latin, this changed to cuprum. From there, Old English speakers began using the word "Coper," which eventually became "copper" as we know it today. This name started being used around the 12th century.

Characteristics

Copper is a soft, bendable metal that conducts heat and electricity very well. Along with silver and gold, it is one of the few metals that has a natural color other than gray or silver. Pure copper has a beautiful orange-red color, but it changes when exposed to air, forming a layer that protects the metal from further damage.

Copper does not react with water, but it can slowly react with air to form a brown-black layer. Over time, it may also develop a green layer, often seen on old roofs and statues. Copper can combine with other elements to form different compounds, and there are many different forms of copper found in nature.

Production

See also: List of countries by copper production

Most copper comes from mines where it is found mixed with other elements, mainly in places called porphyry copper deposits. These mines can be very large and deep, like the ones in Chile, Utah, and New Mexico. Chile is the biggest producer of copper, making more than any other country. Copper can also be taken from special places under the ocean, but this is still being studied.

Copper has been used by people for thousands of years, and most of the copper we use today has been mined since the year 1900. There is a lot of copper in the Earth, but we can only use a small part of it right now. The price of copper changes a lot and can go up and down.

The world needs more copper than ever before, especially for new technologies that use electricity. China uses more copper than any other country.

Most copper comes from ores that contain sulfur. These ores are changed through heating and other processes to make pure copper. Sometimes copper is also found in ores that do not contain sulfur, and these are processed using different methods.

Mining copper uses a lot of energy and can create waste that may harm the environment. Special steps are taken to try to reduce these effects.

Alloys

See also: List of copper alloys

Many useful mixtures, called alloys, are made from copper. Brass is made by mixing copper and zinc. Bronze usually means a mix of copper and tin, but it can be any mix that includes copper, like aluminium bronze. For hundreds of years, copper-tin mixes have been used to make bells; the exact mix changes how the bell sounds and how strong it is. Copper is also a key part of special mixtures used to join pieces of silver and gold in jewelry, changing the color, strength, and melting point of the mixtures. Some mixtures that help join metals without using lead are made from tin and a little copper plus other metals.

The mix of copper and nickel, called cupronickel, is used for coins. The US five-cent coin, called a nickel, is made from 75% copper and 25% nickel. Before cupronickel became common in the second half of the 20th century, some countries used mixes of copper and silver. The United States used a mix of 90% silver and 10% copper in coins until 1965. After that, the half dollar coins were made from 40% silver and 60% copper until 1970. A mix of 90% copper and 10% nickel is used for things that need to resist water, though it can be harmed by certain pollutants. Mixes of copper and aluminium create a golden color and are used in decorations. Shakudō is a special Japanese mix of copper with a small amount of gold that can be treated to turn dark blue or black.

Compounds

Copper makes many different compounds. These compounds usually have copper in two main forms, called +1 and +2. Copper compounds help many chemical and biological processes.

The simplest copper compounds have just two elements. For example, there are copper oxides, sulfides, and materials called halides. Copper also forms many compounds with other materials called ligands. In water, copper changes in a special way when certain substances are added. Some copper compounds are used in laboratories and in products like fungicides.

Copper also forms compounds with carbon, which are very reactive and useful in chemistry. There are also special copper compounds with very high forms of copper, such as copper(III) and copper(IV), found in some materials and proteins.

Biological role

Copper plays an important role in living things. It helps in moving energy and carrying oxygen in our bodies. For example, it is part of a special process in tiny parts of cells where energy is made and stored. Copper also helps in protecting cells from damage by working with proteins that break down harmful substances.

Copper is needed in small amounts by our bodies, but too much can be harmful. Our bodies have ways to manage copper levels to keep us healthy. Different foods contain copper, and there are recommended amounts that people should get each day to stay healthy.

History

Prehistoric

Copper Age

Copper occurs naturally and was used by some of the oldest civilizations. People began using copper around 9000 BC. Before copper, humans used gold and meteoric iron, but not iron that was smelted. The use of copper developed in steps: first, shaping native copper by hitting it, then heating it, melting it, and finally casting it into shapes. The earliest evidence of melting copper comes from around 6,200 to 5,000 BCE in the Balkans and Carpathian Mountains.

In North America, people used copper as early as 7,500 BC around the Great Lakes. By around 6000 BC, people in Michigan were mining copper. Over time, copper objects became more decorative than practical.

The earliest known copper object made using a lost-wax method is an amulet from Pakistan, dating to 4000 BC. Smelting copper was discovered in China before 2800 BC, in Central America around 600 AD, and in West Africa around the 9th or 10th century AD. Mining in the UK has been dated to between 2280 and 1890 BC.

Ötzi the Iceman, who lived around 3300 to 3200 BC, had a copper axe head in his possession.

Bronze Age

Main article: Bronze Age

Natural bronze, a type of copper with silicon, arsenic, and sometimes tin, was used in the Balkans around 5500 BC. Mixing copper with tin to make bronze began about 4000 years after copper smelting was discovered. Bronze objects from the Vinča culture in Europe date to 4500 BC. Artifacts made from copper and bronze alloys have been found in Sumer and Egypt from 3000 BC. Egyptian blue, a blue pigment made from copper, was used in ancient Egypt starting around 3250 BC.

The Bronze Age began in Southeastern Europe around 3700–3300 BC and in Northwestern Europe about 2500 BC. It ended when the Iron Age began, between 2000–1000 BC in the Near East and 600 BC in Northern Europe. Brass, an alloy of copper and zinc, was known to the Greeks and became more common during the Roman Empire.

Ancient and post-classical

The Romans called copper aes Cyprium, shortened to cuprum, which is the source of the English word "copper." Copper was very important to ancient peoples like the Greeks and Romans. In mythology, the goddess Aphrodite (Venus in Rome) was linked to copper because of its beautiful shine and its use in making mirrors. Cyprus, a major source of copper, was sacred to Aphrodite.

Copper was widely used by native peoples of North America, with evidence of use going back 7000 years. Native copper was worked using stone tools on Isle Royale between 800 and 1600 AD. In North America, around 1000–1300 AD, copper was shaped by hammering and heating in the city of Cahokia. Beautiful copper plates from this time have been found around Cahokia.

In South America, a copper mask from Argentina dated to 1000 BC is the oldest known copper artifact from the Andes. Early copper metallurgy in Peru began around 500 BC, with larger production starting around 900 AD during the rise of the Sican culture. This continued through conquests by the Chimor and Inca cultures until the Spanish arrived in 1532.

In Africa, copper was more valued than gold or silver from around 2000 BC until the early 1800s. It was traded widely and used in religious, political, and social roles. Romans used copper for money, and later, coins were made from alloys including brass and copper with lead, tin, and silver.

Modern

The Great Copper Mountain in Sweden was a major mine from the 10th century to 1992. In the 17th century, it provided two-thirds of Europe's copper and helped fund Sweden's wars. Copper has been used in roofing, money, and photography. It was used in sculptures and to build the Statue of Liberty. Copper plating and sheathing were used to protect ship hulls, a method started by the British in the 18th century. The Norddeutsche Affinerie in Hamburg was the first modern electroplating factory, beginning production in 1876.

During the Age of Electricity, from the 1880s to the 1930s, the United States produced a large amount of the world's copper. Major mining areas included Michigan, Butte in Montana, and places in Utah and Arizona. New methods like flash smelting, developed in Finland in 1949, improved copper production.

Applications

See also: Copper in renewable energy

Copper is very useful in many areas. About 60% of copper is used to make electrical wires because it conducts electricity very well. About 20% is used for roofs and pipes, and 15% is used in machines. Copper can also be mixed with other metals to make it stronger, like in brass and bronze. For over 200 years, copper paint has been used on boats to stop plants and shellfish from growing on them. Some copper is used in vitamins and to protect plants from diseases.

Wire and cable

Copper is the best material for electrical wires in most cases. It is used in power plants, homes, phones, computers, and many other electrical devices. About half of all copper mined is used for wires and cables. Copper is chosen because it conducts electricity well, is strong, and can be shaped easily.

For a short time in the 1960s and 1970s, some houses in America used aluminium wires instead of copper, but this caused fires. Safer ways to use aluminium have been found, and it is still used in some places, like the Airbus A380 airplane.

Electronics and related devices

In computers and other electronic devices, copper is often used instead of aluminium because it conducts electricity better. Copper is also used in parts that help spread heat, in magnets, and in tools that control microwaves.

Electric motors

Copper helps make electric motors more efficient. This is important because motors use a lot of the world’s electricity. Using more copper in motors can save energy.

Architecture

People have used copper for buildings for thousands of years because it doesn’t rust easily and lasts a long time. It is used for roofs, gutters, and many other parts of buildings. Copper can also be used inside buildings for walls, doors, and even bathroom fixtures. Over time, copper changes to a green color, which many people like.

Copper can be joined to other metals well and can be shaped using heat.

Antibiofouling

Copper stops many tiny living things from growing on it. This is why it was used on ships to stop sea creatures from sticking to them. Today, copper mixtures are used in nets for fish farms and other places where water can cause problems.

Antimicrobial

Main articles: Antimicrobial properties of copper and Antimicrobial copper-alloy touch surfaces

Surfaces made from copper mixtures can kill many germs, like the ones that cause sickness. This is why some hospitals and public places use copper for things like doorknobs and railings. Copper can also be mixed into fabrics to help stop germs.

Fungicide

Copper is used to protect wood from fungi that can damage it. It is a safer choice than some older materials that could hurt the environment.

Folk medicine

Copper is often made into jewelry. Some people believe that wearing copper bracelets can help with arthritis, but studies have not shown this to be true. Copper does not get absorbed through the skin.